<v-form v-model="valid" ref="form" :class="visibleclass">
    <v-row no-gutters>
        <div class="div-operator">≤</div>
        <v-col cols="12" md="5">
            <v-text-field label="Number" v-model="nTimesUsageValue" @change="nTimesUsageTfChange" :rules="numberRule"
                required :readonly="readonly">
            </v-text-field>
        </v-col>
    </v-row>
</v-form>